You can add an update to your listing by clicking the button shown in the screenshot below.
Sellers can add a separate update to their listing after bids have been placed if the information added is an improvement or clarification of the initial information provided. Images and notes can be added and shipping options can be upgraded up to 24 hours before a listing ends. To update the listing, click the "Update" button on the listing page. Updates are displayed and documented at the bottom of the listing.
However sellers cannot make any edits once a bid has been received. Only updates are allowed. An edit is allowed before a bid is received and an update is allowed after a bid has been received.
Bidders are responsible for carefully reading a listing before placing a bid. Updates that contradict the original description and do not improve the listing are subject for removal.